l. Modulator Valve Body Assembly (fig. 1-27).
The modulator
valve assembly, located under the main valve body cover, is comprised
of the modulator and signal main valve assemblies.
The modulator
valve body assembly consists of a valve body, spring, and actuator in
the modulator body assembly.
Spring pressure moves the valve to the left and compressor discharge
pressure, from the gas turbine engine, moves it to the right. When
running the engine at part throttle, CDP is low and the valve does
not move. Increasing the throttle setting increases the CDP, causing
the CDP actuator and valve to move to the right. The movement to the
right reduces modulator pressure.
Reducing the throttle setting reduces the CDP and allows the spring
to move the valve back toward the left to the different regulating
position. For modulator pressure to be considered regulated, spring
pressure and compressor discharge pressure must be equal.
Thus,
modulation pressure varies with throttle opening.
Figure 1-27.
Modulator Valve.
m. Lube Regulator (Cooler Dump Valve)(fig. 1-28).
The lube
regulator assembly consists of a valve and calibrated spring in a
bore.
When cooler out pressure exceeds the calibrated spring
pressure, the lube regulator valve moves up and allows the pressure
to return to the reservoir.
33
OD1710
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